Pipe coupling



FIG. 1 is an isometric view of our design for a pipe coupling;

FIG. 2 is a right side view thereof, the left side being a mirror imagethereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines depict portions of the pipe coupling that form no partof the claimed design.

CLAIM We claim the ornamental design for a pipe coupling, as shown and described. 